Fruit Juice Samples Research Articles

Effervescence-assisted dispersive liquid-liquid microextraction for the extraction and preconcentration of pesticide residues in fruit juice samples

BackgroundThe widespread use of pesticides for the protection of fruits has resulted in the presence of pesticide residue levels beyond their limit in fruits. This ensures their transfer to processed products, such as juices, posing a threat to human health. Therefore, an efficient and selective method is required for monitoring pesticide residues in fruit juices. Hence, an effervescence-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplets was developed for the simultaneous extraction of five pesticide residues of different classes. An environmentally green low-density organic solvent, 1-undecanol, was used as extraction solvent. (94) ResultsThe developed method was optimized and validated for quantitative extraction of multiclass pesticide residues at trace levels from fruit juice samples, including apple, pineapple, guava and orange samples. The method showed good linearity in the range of 0.8 to 300 ng mL-1 for all pesticide residues with a regression coefficient ranging from 0.9979 to 0.9997 under the optimized conditions. The LOD and LOQ of the method ranged between 0.03-0.16 ng mL-1 and 0.11-0.52 ng mL-1, respectively, indicating the high sensitivity of the proposed method. Repeatability and reproducibility, in terms of %RSD, were obtained in the range of 1.16-5.50% and 3.12-7.72%, respectively. (101) SignificanceThe developed method exhibited acceptable mean recoveries (%R) in the range of 73.77-113.34 % with %RSDs (n=3) ranging from 1.25 to 7.74% for all the analytes studied. Therefore, the developed method can be used as a selective, sensitive and efficient extraction method for the extraction of multiclass pesticides from fruit juice samples. (52)

Ameliorated Viability of Lactic Acid Bacteria in Fruit Juice Isolated from Indigenous Dahi with Prebiotics (Asparagus falcatus and Zingiber officinale)

Dahi is a fermented milk product containing probiotic lactic acid bacteria. This study aimed to isolate, identify, and characterize lactic acid-producing bacteria from native Dahi and evaluate their viability in orange juice using natural prebiotics. Dahi samples were obtained from local shops in Chattogram and Bogura, Bangladesh. Lactic acid-producing bacteria were isolated using MRS (de Mann Rogosa and Sharpe) medium. The isolated bacteria were identified through colony morphology, biochemical tests, and probiotic characteristics. Molecular identification was performed using polymerase chain reaction (PCR) targeting conserved 16S rDNA regions. Isolates of the genus Lactobacillus and Lactococcus lactis sp. Lactis were confirmed and used to develop probiotic orange juice. Prebiotics (Asparagus falcatus and Zingiber officinale) were added to the juice to support probiotic growth. The inoculated cell’s viability and the juice’s physicochemical parameters were evaluated during fermentation (48 hours) and storage (28 days). All fruit juice samples showed a mean number of viable cells of at least 1×105 CFU/mL during the 48-hour fermentation and 28-day storage in the refrigerator. Using natural prebiotics positively affected the survival of lactic acid bacteria, as demonstrated by bacterial colony growth on Petri dishes. Developing probiotic fruit juice enriched with prebiotics could be an effective alternative for individuals allergic or intolerant to milk-based products. Incorporating lactic acid bacteria from native Dahi into orange juice, combined with natural prebiotics, resulted in viable probiotic cells throughout fermentation and storage.

Modification of hollow microporous organic network with polyethyleneimine for efficient enrichment of phenolic acids from fruit juice samples

Owning to the hydrophobic characteristics of microporous organic networks (MONs), their utilizations still largely limited in non- and weak-polar analytes. To expend their applications, here we reported the synthesis of a novel hollowed H-MON-PEI1800–2 composite via sacrifice template method and subsequent modification with polyethyleneimine (PEI) for efficient solid phase extraction of polar and ionic phenolic acid (PAs) from fruit juice samples. H-MON-PEI1800–2 exhibits large surface area, rapid extraction kinetics, remarkable chemical and thermal stabilities, and provides synergistic electrostatic, π-π, hydrogen bonding, and hydrophobic interaction sites for PAs. The developed method owns low limit of detection, wide linear range, large enrichment factors, and good reusability. The recoveries of H-MON-PEI1800–2 for PAs are 1–3 orders of magnitude higher than those of commercial adsorbents like activated carbon, C18 and Oasis HLB. This work highlights the prospects of functional H-MONs for enriching polar and ionic targets from complex sample matrices.

Synthesis of a bimetal-organic framework-cobalt oxide nanoflowers (Ni/Co-MOF@Co3O4 NFs) for sensitive tebuconazole extraction from fruit juice and water samples using micro-solid phase extraction-HPLC-DAD

Tebuconazole (TBZ) is a widely used triazole fungicide that poses potential risks to human health and the environment due to its persistence in food and water. Effective monitoring of TBZ residues is crucial for ensuring food safety and environmental protection. This study presents a novel method for synthesizing Ni/Co-MOF@Co3O4 nanoflowers (NFs) and their application in extracting TBZ from water and fruit juice samples via micro-solid phase extraction (µ-SPE). Ni/Co-MOF@Co3O4 NFs was synthesized using the hydrothermal technique followed by calcination. The synthesized nanoflowers were characterized through SEM, XRD, and FT-IR analyses. Optimal extraction conditions were established at pH 8, using 10 mg of adsorbent, with adsorption and desorption times of 3 and 2 min, respectively. TBZ analysis was conducted using HPLC with a Poroshell 120 EC-C18 column and a diode array detector (DAD). The method demonstrates excellent recovery rates (90–102 %) and RSD% of 3.7 % in spiked fruit juice and natural water samples. The analytical performance showed a wide linear range (1–2000 µg L−1) with a high correlation coefficient (R2 = 0.9998), a detection limit of 4.0 ng L−1, and a quantification limit of 13.0 ng L−1. This approach is fast, simple, and highly sensitive, offering a reliable technique for detecting trace levels of TBZ in food and water environments.

Analysis and Detection of Heavy Metals Content in Some Selected Packaged Fruit Juices of Kathmandu City by Flame Atomic Absorption Spectroscopy

The determination of level of heavy metals in packaged fruit juices is crucial, as extended exposure to even small quantities of these toxic element can cause severe health issues and chronic poisoning. Hence, it is essential to gather comprehensive data on the presence of heavy metals in packaged fruit juice samples. The objective of this research work is to determine heavy metals (Fe, Cu, Zn and Pb) in four different types of packaged fruit juice samples viz Apple, Mango, Orange and Lychee of four different popular brands bought from retail market of Kathmandu city by flame atomic absorption spectroscopy and compare with acceptable limit set by WHO/FAO. Wet acid digestion method was used for digestion process of packaged fruit juice samples. The concentration of Iron were ranged from 0.572-0.762mg/L in Orange juices; 0.362-0.624mg/L in Mango juices; 0.277-3.649mg/L in Apple juices; 0.279-1.770mg/L in Lychee juices respectively. Copper concentration were ranged from not detected (ND)-0.574mg/L in Orange juices; ND for all selected samples in Mango juices; ND- 0.023mg/L in Apple juices; ND-0.041mg/L in Lyclee juices. Similarly Zinc concentration were ranged from 0.0511-0.2026mg/L in Orange juices; ND-0.0700mg/L in Mango juices; ND for all selected samples in Apple juices; ND-0.0287mg/L in Lychee juices. The concentration of hazardous element Lead was found below detection limit in all selected packaged fruit juice samples. The heavy metals concentration in selected brand of packaged fruit juice samples was in following order: Fe>Zn>Cu> Pb. Int. J. Appl. Sci. Biotechnol. Vol 12(3): 158-165.

Efficient Solid-Phase Extraction of Neonicotinoid Insecticides from Environmental Water and Drink Samples Using a Postmodified Metal-Organic Framework.

Neonicotinoid insecticides (NNIs) are extensively utilized globally because of their efficient and broad-spectrum properties. However, their residues are also extensively distributed in the environment. Herein, MIL-101-SO3Na with abundant -NH- and sulfonate groups was synthesized via chloromethylation and nucleophilic substitution postmodification strategies and used to extract NNIs via solid-phase extraction. MIL-101-SO3Na was enhanced by introducing C-H···N hydrogen bonds to strengthen interaction forces and -SO3Na groups to adjust surface charge and enhance electrostatic attraction. This modification and the substantial specific surface area (998 m2·g-1) of the metal-organic framework markedly enhanced the enrichment efficiency of MIL-101. The proposed method based on MIL-101-SO3Na exhibited a minimal detection threshold (0.04-0.87 ng·L-1), an extensive linear spectrum (1-2000 ng·L-1), and notable accuracy (a variation of 3.02-11.8%) in water and drink samples. NNI concentrations between 0.25 and 24.2 ng·L-1 in fruit juice and tea samples were accurately identified using the proposed method, demonstrating its feasibility in practical applications. The postmodification of MIL-101-SO3Na is an exceptional and promising approach for the sensitive detection of ultratrace NNI levels in complex matrices.

Electrochemical detection of salicylic acid in fruit products with ternary ZnO/CuO/Y2O3 nanocomposites embedded PEDOT:PSS by differential pulse voltammetry

In this approach, a novel electrochemical sensor for the determination of salicylic acid (SA) in fruit juices was developed using a nanocomposite (NC) of ZnO/CuO/Y2O3 coated on a glassy carbon electrode (GCE). The ternary metal oxide NCs were synthesized via a facile hydrothermal method and thoroughly characterized using techniques such as X-ray photoelectron spectroscopy (XPS), X-Ray diffraction analysis (XRD), UV–Vis spectroscopy (UV–Vis), Fourier Transform Infrared Spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), and Energy-Dispersive X-Ray Spectroscopy (EDS). The NCs were then used to modify a flat-polished GCE surface, with a conducting polymer binder (PEDOT:PSS) used to facilitate the coating. Differential pulse voltammetry (DPV) was employed for the selective electrochemical detection of SA using this NC-modified GCE sensor. The DPV analysis exhibited a linear relationship between the peak current and SA concentration over a wide range of 1.5 ∼ 15.0 μM, indicating a large linear dynamic range. The sensor demonstrated excellent sensitivity, with a value of 5.79 μA μM−1 cm−2, and a low limit of detection of 0.18 ± 0.09 μM for SA. Additionally, the sensor’s performance was evaluated in terms of pH optimization, response time, stability, reproducibility, and repeatability. Importantly, the developed ZnO/CuO/Y2O3 NC-modified GCE sensor was successfully applied to the analysis of real fruit juice samples, showcasing its potential for practical applications in food analysis and quality control.

An ultrasound assisted dispersive micro solid-phase extraction and a composite ionic liquid-metal organic framework for sixteen polycyclic aromatic hydrocarbons analysis in fruit juice and environmental water samples

Aluminum-based metal organic framework composite containing ionic liquid was prepared and used as sorbent for extraction of sixteen polycyclic aromatic hydrocarbons in list of priority pollutants of United States Environmental Protection Agency before their analysis by gas chromatography/mass spectrometry. The dispersive micro solid-phase extraction method, known as a simple and fast method, was preferred as the extraction method. The optimized parameter conditions were 5 mL of sample solution, 10 min sonication by ultrasonic bath, 30 mg of sorbent, 30 °C extraction temperature, 0.1 mL of hexane as elution solvent with 5 min elution time. The suggested method presented that limit of detection and limit of quantification were in the range of 0.01–0.10 μg l-1, and 0.04–0.33 μg L-1, respectively. The intra-day and inter-day repeatability were within the ranges of 1.18–4.88 % and 1.02–5.06 %, respectively. The recoveries for polycyclic aromatic hydrocarbons in peach juice, cherry juice, tap water and rain water samples were obtained in the range of 84.9–99.9 % for spiked 5, 50 and 100 μg l-1 standard polycyclic aromatic hydrocarbons solution.

Dispersive-solid phase extraction of diniconazole from water and fruit juice samples using MnCoCu-LDHs@MOF-235 nanocomposite

In this study, a new, affordable, and promising adsorbent based on MnCoCu-LDHs@MOF-235(Fe) nanocomposite was successfully synthesized, characterized, and utilized for the solid phase extraction of diniconazole (DNC) pesticide from water and food samples before it was determined by liquid chromatography. The structural characteristics of the synthesized nanocomposite were confirmed by various techniques, including FTIR, XRD, FE-SEM, and FE-SEM-EDX. The central composite design (CCD) technique was used for multi-response optimization of effective parameters including the sample solution’s pH (6.0), adsorbent amount (15 mg), adsorption time (5 min), sample volume (30 mL) and eluent volume (2.5 mL), and desorption time (3 min) to achieve optimum extraction efficiency. Under optimal conditions, the method’s analytical performance was assessed. The results showed that the calibration graphs showed linearity for DNC in the range of 1.3–500 µg L−1, with a detection limit of 0.4 µg L−1 and a correlation coefficient of 0.9988. Additionally, 2.9 intra-day RSD, 6.1 inter-day RSD, 12.0 preconcentration factor, and 2.53–11.53 enrichment factors was attained. The performance of the method to extract DNC from nine different real samples was realized with high relative recoveries (88.0–108 %). In addition, the greenness of the method was assessed with the AGREE metric tool, confirming that the method is environmentally friendly.

Preparation of microelectrode based on molecularly imprinted monolith using ionic liquids as functional monomers for specific separation and enrichment of phenolic acids

Efficient and specific isolation and capture of phenolic acids (PAs) in complex samples is challenging due to its high polarity. In this study, combining the merits of porous monolith, ionic liquids, molecularly imprinted polymer and electroenhanced solid-phase microextraction (EE-SPME), a new sample pretreatment method was developed for the selective isolation and extraction of PAs. Using vanillic acid (VA) as template molecule, mixed ionic liquids including 1-allyl-3-methylimidazoliumbis[(trifluoromethy)sulfonyl]imide and N,N,N-trimethyl-1-(4-vinylphenyl)methanaminium chloride were chosen as dual functional monomers, a molecularly imprinted monolith-based microelectrode (MBM) was in-situ fabricated. Under the EE-SPME format, the extraction behaviors and specific recognition performance of MBM towards VA and its structural analogues were investigated in detail. Results revealed that the exertion of electric field during extraction period increased the imprinted factors from 1.57–1.77 to 1.87–2.23. Under the beneficial parameters, a sensitive and reliable approach for the quantification of PAs contents in water and fruit juice samples by the combination of MBM/EE-SPME with HPLC technique was developed. The achieved limits of detection ranging from 0.012 μg/L to 0.11 μg/L and 0.042 μg/L to 0.15 μg/L for waters and juices, respectively, and the recoveries with different spiked concentrations in actual sample were 83.1–110 %. In comparison with the existing approaches, the established method presented some characteristics in the analysis of PAs, such as simplicity, high cost-effectiveness, good anti-interference performance, satisfactory sensitivity and low consumption of solvent.

Investigation of the formation of furfural compounds in apple products treated with pasteurization and high pressure processing

The thermal treatment carried out in the processing of apple products is very likely to induce Maillard reaction to produce furfurals, which have raised toxicological concerns. This study aimed to elucidate the formation of furfural compounds in apple products treated with pasteurization and high pressure processing (HPP). The method for simultaneous determination of five furfural compounds including 5-hydroxymethyl-2-furfural (5-HMF), furfural (F), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), 2-acetylfuran (FMC), and 5-Methyl-2-furfural (MF) using high performance liquid chromatography equipped with diode array detector (HPLC-DAD) was successfully developed and validated. All five furfurals exhibited an increasing trend after the pasteurization treatment of apple clear juice, cloudy juice, and puree. 5-HMF, F, FMC, and MF were increased significantly during the precooking of apple puree. Whereas there was no significant change in the furfurals formation after apple products treated with high pressure processing (HPP) with 300 MPa and 15 min. Based on the variation of the fructose, glucose and sucrose detected in apple products after thermal treatment, it revealed that the saccharides and thermal treatment have great effect on the furfural compounds formation. The commercial fruit juice samples with different treatments and fruit puree samples treated with pasteurization were also analyzed. Five furfurals were detected more frequently in the fruit juice samples treated with pasteurization or ultra-high temperature instantaneous sterilization (UHT) than those treated with HPP. 5-HMF and FMC were detected in all fruit puree samples treated with pasteurization, followed by F, MF, and HDMF with the detection rate of 79.31 %, 72.41 %, and 51.72 %. The results could provide a reference for risk assessment of furfural compounds and dietary guidance of fruit products for human, especially for infants and young children. Moreover, moderate HPP treatment with 300 MPa and 15 min would be a worthwhile alternative processing technology in the fruit juice and puree production to reduce the formation of furfural compounds.

In situ formation of an adsorbent using a mixture of ibuprofen and choline chloride for the extraction of Cu(II) and Cd(II) ions from water and fruit juice samples combined with dispersive liquid–liquid microextraction

In situ formation of an adsorbent using a mixture of ibuprofen and choline chloride for the extraction of Cu(II) and Cd(II) ions from water and fruit juice samples combined with dispersive liquid–liquid microextraction

A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides

A magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@N-GQDs@Fe3O4NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding with triazines. The MIP layer provided highly specific recognition sites for the selective adsorption of three target triazines. The extracted triazines were determined by high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD). The developed method exhibited linearity from 1.5 to 100.0 µg L−1 with a detection limit of 0.5 µg L−1. Recoveries from spiked fruit juice samples were in the range of 80.1– 108.4 %, with a relative standard deviation of less than 6.0 %. The developed MMIP adsorbent demonstrated good selectivity, high extraction efficiency, ease of fabrication and use, and good stability.

Glutathione‑iron hybrid nanozyme-based colorimetric sensor for specific and stable detection of thiram pesticide on fruit juices

Given the potential dangers of thiram to food safety, constructing a facile sensor is significantly critical. Herein, we presented a colorimetric sensor based on glutathione‑iron hybrid (GSH-Fe) nanozyme for specific and stable detection of thiram. The GSH-Fe nanozyme exhibits good peroxidase-mimicking activity with comparable Michaelis constant (Km = 0.551 mM) to the natural enzyme. Thiram pesticides can specifically limit the catalytic activity of GSH-Fe nanozyme via surface passivation, causing the change of colorimetric signal. It is worth mentioning that the platform was used to prepare a portable hydrogel kit for rapid qualitative monitoring of thiram. Coupling with an image-processing algorithm, the colorimetric image of the hydrogel reactor is converted into the data information for accurate quantification of thiram with a detection limit of 0.3 μg mL−1. The sensing system has good selectivity and high stability, with recovery rates in fruit juice samples ranging from 92.4% to 106.9%.

Biochemical characterization of a novel acid-active endopolygalacturonase for pectin depolymerization, pectic-oligomer production, and fruit juice clarification

Endopolygalacturonases are crucial pectinases known for their efficient and sustainable pectin depolymerization activities. The present study identified a novel gene encoding endopolygalacturonase from an acidic mine tailing metagenome. The putative gene showed a maximum identity of 67.55 % with an uncharacterized peptide sequence from Flavobacterium fluvii. The gene was cloned and expressed in a heterologous host, E. coli. Biochemical characterization of the novel endopolygalacturonase enzyme variant (EPHM) showed maximum activity at 60 °C and at 5.0 pH, while retaining 50 % activity under the temperature and pH range of 20 °C to 70 °C for 6 h, and 3.0 to 10.0 for 3 h, respectively. The enzyme exhibited tolerance to different metal ions. EPHM was characterized for the depolymerization of methylated pectin into pectic oligosaccharides. Further, its utility was established for fruit juice clarification, as endorsed by high transmittance, significant viscosity reduction, and release of reducing sugars in the treated fruit juice samples.

NiFe-LDH/nylon 6 composite electrospun on polypropylene membrane: A new extractive device development for porous membrane protected micro-solid-phase extraction of organophosphate pesticides from fresh fruit juice samples coupled with liquid chromatography tandem mass analysis

A unique strategy for developing porous membrane protected micro-solid phase extraction has been provided. An electrospun composite was fabricated on the sheet of membrane. To this end, NiFe-layered double hydroxide/Nylon 6 composite nanofibers were coated on a polypropylene membrane sheet followed by folding into a pocket shape, which were then utilized as a novel extractive device to extract of organophosphorus pesticides from fresh fruit juice samples prior to liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis. The fabricated hybrid composites were successfully characterized. The effective parameters on extraction performance were investigated. LODs were 0.020–0.065 ng mL−1. Excellent linearity (R2≥0.996) was observed between 0.05 and 100.0 ng mL−1. RSDs% were in the range of 3.1–5.8% (intra-day, n = 3) and 2.6–5.5% (inter-day, n = 3×3). Satisfactory related recovery values within the acceptable range of 90.7–111.2% with RSDs% below 6.7% were achieved for the analysis of real samples.

Waste hazelnut shell based effective hydrothermal carbon/SnO2 nanoparticles: Towards electrochemical sensing of catechol in green tea, fruit juice, and urine samples

This study focused on the electrochemical detection of catechol (CC), a carcinogenic for humans and a periodic environmental pollutant found in consumed food and beverages and has low degradability and high toxicity in the ecological environment. Also, in this study, for the first time, a new and green electrochemical detection platform was developed for the detection of CC through green carbon material (HZ) recycled from waste hazelnut shells with the hydrothermal carbonization technique (HTC) and SnO2 nanoparticles (NPs). The morphology, surface chemistry, chemical structure, and physicochemical properties of the synthesized green-based functional carbon material and SnO2 NPs were thoroughly investigated and elucidated using different characterization techniques. Thus, a green perspective was contributed to the studies of researchers working on CC detection in designing new types of nanosensors and developing electrode modifications. On GCE with an HZ-SnO2 modification, the effects of pH, the supporting electrolyte, and the scan rate on the electrochemical behavior of CC were investigated. The limit of detection (LOD) of the proposed nanosensor for CC was determined as 8.51 nM and the linearity range was determined as 0.80–80 µM under optimal conditions using adsorptive stripping differential pulse voltammetry (AdsDPV).The developed new type, the green method, has been performed to detect the CC in green tea, fruit juice, and urine samples with sufficient accuracy and precision.

Development of a pH-responsive ratiometric fluoroprobe based on GSH-CuNCs-Ce3+ and N-CQDs for rapid/sensitive malathion detection in fruit juices

Herein, we engineered a novel pH-responsive ratiometric assay by virtue of the composite system of Ce3+-enhanced glutathione-encapsulated copper nanoclusters (GSH-CuNCs-Ce3+) and N-doped carbon quantum dots (N-CQDs). The GSH-CuNCs-Ce3+ and N-CQDs were fabricated using one-pot chemical reduction and hydrothermal approaches, respectively, and their morphologies as well as physical and chemical properties were testified in detail by a series of characterization techniques. At 350 nm excitation wavelength, the GSH-CuNCs-Ce3+/N-CQDs system (GCC-NC) featured the 440/650 nm dual-emitting property. The ratios of fluorescence intensities (F650/F440) demonstrated a strong pH-dependence from 3.0 to 5.0 with a coefficient of determination of 0.9982. Consequently, the GCC-NC system was feasible for constructing a pH-responsive dual-emitting fluoroprobe. Based on the catalytic effect of acetylcholinesterase on acetylcholine to yield acetic acid and further trigger varying solution pH, the as-constructed GCC-NC fluoroprobe was satisfactorily applied for detecting malathion. Under optimized conditions, the newly developed GCC-NC fluoroprobe supplied a wider linear range (0.25–200 μM), lower detection limit (0.075 μM), satisfactory recoveries (96.3–106.2%) and higher precision for malathion in several kinds of fruit juice samples. The fortified experiments by malathion’s structural analogues and metal ions provided compelling evidence that this fluoroprobe had strong anti-interference capacity and high specificity for malathion. These findings render us to believe that the as-constructed pH-responsive dual-emitting fluoroprobe holds great promise in trace malathion assay in food matrices.

Establishment of multivariate digital high performance liquid chromatography fingerprints of fruit juice essence and its flavor quality evaluation

Quality control problem of essence and spices has always been the focus of food chemists in recent years. In this study, a multi-variate digital fingerprint profile of fruit juice essence sample was established using the combination of HPLC-DAD spectra and UPLC-MS spectra, which were collected to obtain the information about organic acids, polyphenols, sugars and sugar alcohols of the samples. The stability, reliability and repeatability of the combined fingerprinting method were verified in the work. A total of 36 markers in the established fingerprint were common (20 compounds were confirmed) belonging to different classes: organic acids, polyphenols, sugars, sugar alcohols, and other miscellaneous compounds. Those chromatographic peaks that significantly affect the quality of apple juice flavor were screened from principal component analysis (PCA). Moreover, PCA and cluster analysis of the proposed combined fingerprint gave the better evaluation of the sample quality stability and distinguish sample groups than the fingerprint from single data, which demonstrated its great significance to the quality control of fruit juice samples.

Development of a continuous magnetic dispersive solid phase extraction method for the extraction of seven widely used pesticides from fruit juices

Generally, food safety monitoring is vital issue to preserve human health and guarantee a longer lifespan. In present study, a continuous mode of magnetic dispersive solid phase extraction method based on using magnetic covalent organic framework@metal organic framework nanocomposite as sorbent has been proposed. The developed method has been tested for the extraction of some pesticides (pirimicarb, terbutryn, fenthion, triticonazole, hexaconazole, diniconazole, and haloxyfop-R-methyl) from commercial fruit juices prior to their analysis by high performance liquid chromatography–tandem mass spectrometry. In the current research, the properties of nanocomposite were characterized by scanning electron microscopy, Fourier–transform infrared spectrophotometry and X–ray diffraction techniques. In the next step, the synthesized nanocomposite was employed as an efficient sorbent in the developed extraction procedure that was done in a narrow bore tube. Under optimum extraction conditions, extraction recoveries were in the ranges of 67–83 %. Moreover, the limits of detection and quantification of the selected analytes were in the ranges of 17–43 and 56–143 ng L−1, respectively. Finally, the proposed method was successfully applied in the analysis of the opted pesticides in sixty fruit juice samples.